Reinforcing Increase of ΔTc in MgB2 Smart Meta-Superconductors by Adjusting the Concentration of Inhomogeneous Phases

Abstract

Incorporating with inhomogeneous phases with high electroluminescence (EL) intensity to prepare smart meta-superconductors (SMSCs) is an effective method for increasing the superconducting transition temperature (Tc) and has been confirmed in both MgB2 and Bi(Pb)SrCaCuO systems. However, the increase of ΔTc (ΔTc = Tc ‒ Tcpure) has been quite small because of the low optimal concentrations of inhomogeneous phases. In this work, three kinds of MgB2 raw materials, namely, aMgB2, bMgB2, and cMgB2, were prepared with particle sizes decreasing in order. Inhomogeneous phases, Y2O3:Eu3+ and Y2O3:Eu3+/Ag, were also prepared and doped into MgB2 to study the influence of doping concentration on the ΔTc of MgB2 with different particle sizes. Results show that reducing the MgB2 particle size increases the optimal doping concentration of inhomogeneous phases, thereby increasing ΔTc. The optimal doping concentrations for aMgB2, bMgB2, and cMgB2 are 0.5%, 0.8%, and 1.2%, respectively. The corresponding ΔTc values are 0.4, 0.9, and 1.2 K, respectively. This work open a new approach to reinforcing increase of ΔTc in MgB2 SMSCs.

Critical Current Density and Meissner Effect of Smart Meta-Superconductor MgB2 and Bi(Pb)SrCaCuO

“…The curve of the temperature dependence of resistivity ( R – T ) shows that the non-luminescent dopants Y 2 O 3 and Y 2 O 3 :Sm 3+ doping decreases the T C of MgB 2 , while the luminescent inhomogeneous phase Y 2 O 3 :Eu 3+ and Y 2 O 3 :Eu 3+ +Ag doping increases the T C of MgB 2 in different amplitudes. The preparation process and related characterization of pure MgB 2 and doped MgB 2 samples were described in [ 44 ].…”

“…The smart meta-superconductors are composed of superconducting particles and Y 2 O 3 :Eu 3+ and Y 2 O 3 :Eu 3+ +Ag luminescent inhomogeneous phases. We doped Y 2 O 3 :Eu 3+ and Y 2 O 3 :Eu 3+ +Ag EL materials in conventional MgB 2 and high-temperature Bi(Pb)SrCaCuO superconductors [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. The research results showed that the doping of Y 2 O 3 :Eu 3+ and Y 2 O 3 :Eu 3+ +Ag EL materials increases the T C of MgB 2 and Bi(Pb)SrCaCuO.…”

“…EL energy injection promotes the formation of electron pairs. Accordingly, the T C of MgB 2 and Bi(Pb)SrCaCuO can be increased via EL [ 43 , 44 ].…”

An Improved Smart Meta-Superconductor MgB2

“…When the Tc of SMSCs is measured by the four-probe method, the external electric field can stimulate the inhomogeneous phase to produce EL, which can achieve the purpose of strengthening the Cooper pair and lead to the macroscopic change of Tc. SMSCs is a material that can adjust and improve Tc through external field stimulation, which is a new property that cannot be achieved by traditional second phase doping [44][45][46]. The results show that doping of Y2O3:Eu 3+ and Y2O3:Eu 3+ +Ag EL materials increases TC of MgB2 and Bi(Pb)SrCaCuO.…”

“…In recent years, MgB2 and Bi(Pb)SrCaCuO smart meta-superconductors have been constructed, SMSCs consist of superconducting particles and Y2O3:Eu 3+ or Y2O3:Eu 3+ +Ag luminescent inhomogeneous phases. We doped Y2O3:Eu 3+ and Y2O3:Eu 3+ +Ag materials in conventional MgB2 and high temperature Bi(Pb)SrCaCuO superconductors [40][41][42][43][44][45][46][47]. In this method, the electroluminescent (EL) material is directly doped into the superconductor to form a smart meta-superconductor.…”